Prenatal consent will be obtained on infant's with estimated gestational age up to 28+6 weeks. Shortly before delivery, infant's will be randomly assigned to receive either Low oxygen concentration (FiO2 .30) OR High oxygen concentration (FiO2 1.0) during 90 seconds of delayed cord clamping.
Randomization and intervention will remain blinded to the clinical care team during the entire study period. The research team member will open a randomization card when notified of a subject's impending birth, review the protocol with the obstetric provider performing the procedure, set-up the sterile stabilization bed, and note the time it takes from delivery until the clamping and cutting of the umbilical cord in both groups.
The research team member will set the oxygen blender as indicated by the randomization card and cover the blender to blind the FiO2 setting. The research team member will not be involved in the clinical care of the infant. The oxygen blender will be concealed from the clinical care team to ensure resuscitation maneuvers will not be biased.
Data will be submitted to the statistician, who will remain blinded to the intervention for the duration of the study.
At delivery, the infant will be placed on a platform that allows the infant to be close to the mother and the umbilical cord to remain intact for DCC. These beds are equipped with an oxygen blender, humidifier, t-piece resuscitator with mask, necessary to provide CPAP/PPV. At some centers the bed will be equipped with a radian warmer (Ceramotherm, Wyer GmbH, Germany) to maintain thermoregulation on the infant during delayed cord clamping.
If an infant is randomized to the DCC and Low Oxygen concentration (DCC LO group), the following procedure will ensue:
During delayed cord clamping, the infant will be gently stimulated by drying the infant with a sterile towel and provide CPAP by 30 seconds of life. During delayed cord clamping, breathing assistance with CPAP of 5 cm H20 and a FiO2 0.3 will be provided.
If an infant is randomized to the DCC and High Oxygen concentration (DCC HI group), the following procedure will ensue:
During delayed cord clamping, the infant will be gently stimulated by drying the infant with a sterile towel and provide CPAP by 30 seconds of life. During delayed cord clamping, breathing assistance with CPAP of 5 cm H20 and a FiO2 1.0 will be provided.
Patency of the airway in both groups will be assessed by a Colorimetric CO2 detector. Lack of color change will indicate that the airway is not patent (obstructed), the pressure is not sufficient to expand the lungs, there was excessive air leak, or there was no or inadequate pulmonary blood flow. If there is no color change, the neonatal provider will reposition and reattempt to open the airway, if no improvement they will initiate PPV (starting PIP of 20 cm H20) by 60 seconds of life. Cord clamping will occur at 90 seconds or greater and the infant will be transferred to a standard neonatal warmer and resuscitated per NRP guidelines.
Additionally, when available heart rate data will be collected using a non-invasive dry-electrode monitor, (NeoBeat, Laerdal Medical, Stavanger, Norway) and applied over the infant's chest or abdomen to provide continuous display of heart rate during 90 seconds of DCC.
Pulse oximetry, ECG sensors and Near-Infrared Spectroscopy (NIRS) sensors will be applied after cord clamping. The NIRS sensor will be placed on the infant's forehead. Cerebral StO2, SpO2, blood pressure (once in the NICU) and Heart rate will be recorded every two seconds and linked with other variables. These variables will continue to be recorded for the first 24 hours of life.
Blood sample will be collected at two different time points: Cord blood sample (T1: Cord blood collected after the cord is cut) and at 2 hours of life or NICU admission (T2). This is extra few drops of blood that is drawn from the baby for medical purposes (cord blood from cord gases and admission blood work up).
Samples will be tested for oxidized and reduced glutathione which are the most reliable and comprehensive biomarkers of oxidative stress.
